Teams of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) may support a battalion of human fighters on a battlefield by moving in advance of the battalion, acting as scouts and as armed reconnaissance vehicles. The UAVs may act as teams or as independent entities. The UAVs may communicate over networked radio links between each other and to one or more human commanders. As the UAVs travel along trajectories, obstructions such as hills and trees may interrupt line-of-sight (LOS) between the UAVs. Consequently, direct data links between the UAVs may be interrupted.
An interruption may occur during difficult and treacherous combat situations and may result in loss of a UAV. For example, a UAV may sense an enemy and transmit a location and image of the enemy to a commander, requesting instructions. The commander may transmit an instruction to the UAV to take evasive maneuvers. However, if LOS interruption occurs in that transmission and the transmission is not received by the UAV, the UAV may be subsequently destroyed by enemy action.
A LOS interruption may typically be addressed on the battlefield through the use of relay towers, terrestrial reflectors, and/or high flying aircrafts providing the function of relays forming an interconnection point between two UAVs lacking LOS between them. A relay, if available, may provide a “one more hop” route for transmission of messages between the two UAVs.
Such external relay agents (towers, terrestrial reflectors, high flying aircrafts, etc.) may not be available in forward regions of battlefields. When available, an infrastructure of land lines, relay towers, high flying relay aircraft, and satellites typically may provide a network of alternative routes for these UAV messages. This set of relays and routers may be managed to provide a specific quality of service (QOS) to the network and to react to demands on the network for maintaining a minimum level of QOS. Network control may be centralized, decentralized, or a hybrid of both. Network control algorithms may be predicated upon a specified number of UAVs in the network and random movements of the UAVs with pseudo-random messages between the UAVs at random times.
Conventional approaches for managing the relays and routers have a number of shortcomings. For example, assumptions about the randomness of movements of the UAVs and their message traffic may represent only first order approximations. These assumptions do not consider that patterns of movement of the UAVs, as the UAVs carry out their mission, follow certain trajectories that may be known. Although trajectories may vary throughout a mission, such variations may be within known parameters and hence their position may be predictable.
The volume and pattern of message traffic between UAVs may also be at least partially ordered. For a particular team of UAVs, on a specific mission, there may generally be light message traffic as the UAVs move towards a target, moderate traffic as the UAVs perform targeting functions, high traffic when the UAVs engage in combat, and light traffic as the UAVs leave a target area. Consequently, the magnitude and type of messages for a particular UAV team may be predicted.
However, conventional management of a radio network is planned and sized for pseudo-random movement of the UAVs and pseudo-random messages. When combat ensues, the message traffic will increase in what would appear to be a burst or leap in magnitude of message traffic that may overload the radio network. Loss of LOS or degradation of QOS between UAVs at critical times may result in a message not being received, an acknowledgement not being sent, retransmission of the message, any of which may result in additional strain on the radio network.
A crucial time may be during combat as the UAVs move to avoid detection or to avoid receipt of enemy fire. The management of a network may react to the loss of LOS or degradation of QOS connectivity by changing routing algorithms thereby resulting in additional strain on the radio network more hops for a message to reach its destination. Since this conventional management is reactive in nature, there may be a delay while the network reforms and delivery of messages may be delayed, perhaps jeopardizing survival of one or more UAVs.